The subject matter of this specification relates generally to search systems.
Web search engines today often complement the search results with a list of related search queries. For example, given the query “mars,” a search engine can return the related queries “mars god of war,” “mars planet,” “venus,” “jupiter,” etc. These related search queries help users to find and explore information related to the original query. Furthermore, because users often provide short queries with little or no context, related queries allow users to further specify their information needs. For example, by clicking on “mars god of war,” a user signals interest in the Roman god as opposed to the planet Mars.
Related queries are typically mined from the query logs by finding other queries that co-occur in sessions with the original query. Specifically, query refinements, a particular kind of related queries, are obtained by finding queries that are most likely to follow the original query is a user session. For many popular queries, there may be hundreds of related queries mined from the logs using this method. However, given the limited available space on a search results page, search engines typically only choose to display a few of the related queries.